This invention relates to an electrically released brake of the type in which an electromagnet, an armature, a ring of friction material and an end plate are sandwiched together in an assembly. The ring of friction material is rotatable relative to the other elements of the assembly and is adapted to be connected to a driven member such as a rotatable shaft whose motion is to be retarded by the brake.
Upon energization of the electromagnet, the armature is drawn away from the ring of friction material and toward the electromagnet to release the brake. When the electromagnet is de-energized, springs associated with the electromagnet press the armature against the friction material and press the friction material against the end plate so as to apply the brake and frictionally retard rotation of the shaft.
To help optimize the braking torque and service life of a given brake, it is necessary to establish an air gap of predetermined axial width between the electromagnet and the armature. In prior brakes of this general type, the width of the air gap is established by manually adjusting screws or the like which hold the electromagnet, the armature and the end plate in assembled relationship. Trial and error is required to make such adjustments and thus the assembly procedure is relatively expensive and, in addition, the gap is not always established with the optimum width.